This invention relates to connectors for spaced metal parts, for example a pair of light metal plates disposed parallel to one another, comprising a one-piece plastics core which is held or anchored to the metal parts and is displaceable in the longitudinal direction of the connector.
As is known, metal parts such as metal plates, for example used for windows and doors, have to be held apart so as to provide heat insulation between them. Various heat insulating connections have been used for this purpose. Thus for example it is known to keep the two metal plates spaced from one another by tools and to make a connector strip from a plastic foam; this system involves heavy machine and tool outlay; in many instances the stability of the foam cells breaks down as a result of changes in thermal condition or the metal plates. Since the foam plastic connection is only releasable with difficulty, if at all, from the metal parts it is impossible to subsequently handle these parts, for example for anodising. U-shaped solid plastic profile shapes are known which can be brought in mirror image fashion into the jointing area to define a hollow space which is then filled with plastics foam. This again demands a heavy outlay in machine and tool costs; where there are thermal fluctuations the profile shapes may be contracted, particularly where the connection between the foam plastic and the metal parts demand an intimate adhesion. Any metal parts damaged in this way can only be subsequently anodised with difficulty.
It is also known to use a strip which is constituted by a completely plastic profile and can be drawn laterally into an accommodating cavity at the intended connection site. A solid profile of this nature is on the one hand difficult to introduce over long lengths, and on the other hand involves heat barrier problems, if only because of the uniform degree of hardness thereof.
It is an object of this invention to provide a connector of the type set forth above which exhibits good heat insulating properties.
Another object is to provide a connector which can be introduced very simply into the required working position.